Changing oil tubes in a carbon black reactor

ABSTRACT

A carbon black reactor is equipped with multiple feedstock nozzles which revolve into axial alignment with the reactor throat.

BACKGROUND

This invention relates to carbon black production. In one aspect, theinvention relates to an apparatus for producing carbon black. In anotheraspect, the invention relates to a method for producing carbon black.

In the production of carbon black in reactors utilizing axialintroduction of the carbonaceous make oil into the reaction flow passagefrom the upstream end of the reactor, it is frequently desirable tochange the nozzle through which make oil is emitted into the reactionflow passage, since the properties of the carbon black being producedcan be thus varied. For example, it can sometimes be desirable to changefrom a nozzle which emits feedstock at an included angle of 20° to anozzle which emits feedstock at an included angle of 60°.

It would frequently take an hour or more in the prior art to make theswitch between the feedstock nozzles using two or more operators. Wheresoft black was being produced by heat from the partial burning of thecarbonaceous feedstock, pulling the old nozzle from the reactor wouldresult in the loss of reactor off-gas. Downstream equipment would beginto cool, making possible the formation of acidic condensate. Condensateformation is very undesirable, as the acid condensate can attackdownstream equipment, particularly the filter bags. Additionally, thewet pellet dryer is frequently heated in part by reactor off gas, andwhen the reactor was taken off line as during a nozzle change, the dryerwould have to be heated entirely with fuel gas, an additional expense.Obviously, it would be desirable to accomplish the nozzle changeover asquickly as possible.

OBJECTS OF THE INVENTION

It is thus an object of this invention to provide method and apparatusto effect a quick nozzle change in a carbon black reactor.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, in a carbonblack reactor comprising a generally cylindrical reaction chamber havinga longitudinal axis, said generally cylindrical reaction chamber beingbounded at an upstream end by an upstream end wall, the improvement isprovided which comprises in association with the upstream end wall ameans for positioning at least two feedstock tubes, each feedstock tubehaving a longitudinal axis, with the longitudinal axis of each tubebeing parallel to the longitudinal axis of the generally cylindricalreaction chamber, said means for positioning at least two feedstocktubes being rotatable about a longitudinal axis generally equidistantfrom and generally parallel to the longitudinal axes of the at least twofeedstock tubes and being positioned so that each feedstock tube isrevolvable into axial alignment with the longitudinal axis of thegenerally cylindrical reaction chamber. With this specially designedreactor, the amount of time during which the carbon black reactor is offline for a nozzle change can be reduced to a matter of seconds.

According to another aspect of the present invention, a method isprovided comprising introducing a carbonaceous feedstock into thereaction flow passage of a carbon black reactor through a firstfeedstock tube, positioning a second feedstock tube parallel to a firstfeedstock tube, shifting the second feedstock tube into the positionwhich was occupied by the first feedstock tube and introducing thecarbonaceous feedstock axially into the carbon black reactor through thesecond feedstock tube. The method is advantageously practiced with thereactor provided in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side sectional view, partially in schematic, showing certainfeatures one embodiment of the present invention.

FIG. 2 is an end view of the apparatus of FIG. 1, taken along theindicated lines of FIG. 1, and illustrating certain features of thepresent invention.

DETAILED DESCRIPTION OF THE DRAWINGS

According to the invention, an apparatus 2 for the manufacture of carbonblack comprises a mass of refractory material defining a generallycylindrical precombustion chamber 6 having a longitudinal axisrepresented by the dashed line 8. The chamber 6 is bounded at itsupstream end by an upstream end wall 10. In association with theupstream end wall 10 there is provided a means 12 for positioning atleast two feedstock injectors 14 each of which has longitudinal axiswith the longitudinal axis of each feedstock injector 14 being parallelto the longitudinal axis 8 of the generally cylindrical precombustionchamber 6. The means 12 for positioning the at least two feedstockinjectors is rotatable around its longitudinal axis, which isillustrated by the dashed line 16. The longitudinal axis 16 of the means12 is generally equidistant from and generally parallel to thelongitudinal axis of the at least two feedstock injectors 14 and ispositioned so that each feedstock injector 14 is revolvable into axialalignment with the longitudinal axis 8 of the generally cylindricalprecombustion chamber 6.

Preferably, the means 12 comprises a plate 18 having a first surface 20and an opposite second surface 22 with at least two tubular members ornipples 24 extending generally normally from the first surface 20 with apassage 26 through each tubular member 24 which passes through the plate18, with each passage 26 being adapted for receiving a feedstockinjector 14. The plate 18 is positioned in sealing relationship with apassage 28 which extends through the upstream end wall 10 of the reactor2. The plate 18 is positioned so that the second surface 22 faces thegenerally cylindrical precombustion chamber 6 and is generally parallelto the upstream end wall 10.

Preferably, the plate 18 is in sealing relationship with an upstream end32 of a tubular member 30. At the downstream end 34 of the tubularmember 30 there is a radially outwardly extending flange 36 suitablyfastened to the upstream end wall 10 of the reactor 2 by means such asbolts 38. The flange 36 circumscribes the passage 28 which extendsthrough the upstream end wall 10 of the reactor 2. The tubular member 30preferably extends generally normally from the upstream end wall 10 ofthe reactor 2 away from the generally cylindrical precombustion chamber6.

Preferably, a collar 40 threadably engages the exterior of the tubularmember 30 at its upstream end 32 and positions the plate 18 in acovering relationship with the upstream end 32 of the tubular member 30by urging against the plate 18 via radially outwardly extending shoulderportion 41 and is preferably generally annularly shaped. It is desirablethat an annular gasket 42 be positioned between the shoulder 41 of theplate 18 and the upstream end 32 of the tubular member 30. It is furtherdesirable that a suitable lever receiving means such as nut 44 beaffixed to the surface 20 of the plate 18. In the illustratedembodiment, the nut 44 is welded to the plate 18 along the longitudinalaxis 16. The collar 40 is preferably provided with a wrench-receivingexterior shape, such as a hexagonal perimeter when taken in sectionalacross the axis 16.

During changeover operations, a feedstock injector 14 is positioned inthe passage 26 which passes through each nipple 24. Collars 46preferably threadably engage the exterior of the nipples 24 at theirupstream ends and position a flange 48 affixed to each of the feedstockinjectors 14 in covering relationship with the upstream end of eachtubular member. Preferably, an annular gasket 50 is positioned betweenthe flange 48 and the upstream end of each tubular member to aid informing a reliable seal.

In the illustrated embodiment, each feedstock injector 14, commonlyreferred in the art as "an oil gun" comprises an inner tubular member 52or 53 which carries oil concentrically disposed within an outer tubularmember 54 or 55 which carries air for cooling. The inner tubular member52 or 53 discharges through a nozzle 56 or 57, respectively, and intothe precombustion zone 6. Generally, during the nozzle changeover, thenozzles 56 provided on the end of the oil tube 52 will be different forproducing different carbon blacks, from the nozzle 57 provided on theend of the oil tube 53, although the invention provides its benefitseven where the nozzle are the same, e.g., if nozzle 56, shown ason-stream, is plugging as by coking.

Generally, each tube 52 or 53 is connected to an oil source 58.Preferably each tube 52 or 53 is connected to a flexible oil line 60 or61 and a valve 62 or 63 is positioned between the flexible line 60 or 61and the oil source 58. The air tube 54 or 55 is connected to an airsource 64. Air source 64 is connected to flexible hoses 65 and 66 tocooling air tubes 54 and 55, respectively. Hoses 65 and 66 have controlvalves 67 and 68 therein respectively. The oil gun on stream normallyhas about 4,000 standard cubic feet per hour of cooling air passedthereto, as via hose 65 in the FIG. 1. Cooling air is also preferablyadded to the oil gun off-stream as via conduit 66. Normally about 4,000standard cubic feet of cooling air per hour is added also to theoff-stream oil gun to prevent overheating of the gun.

In the use of the apparatus 2 to manufacture carbon black, hot air orcombustion gases are introduced into the zone 6 via tangential tunnels76. In the illustrated embodiment, "hard" black would preferablybemanufactured, and the tunnels 76 would carry combustion gases, althoughit is to be understood that the present invention also is applicable tothe manufacture of "soft" carbon blacks, in which event the tunnels 76would usually carry heated air. For the manufacture of hard blacks, thezone 6 is preferably connected to a zone 78 which has a smaller diameterthan the zone 6 and, if desired, can be provided with a venturi 80 foran improved flow pattern in the reaction mass.

The method according to the present invention comprises introducing acarbonaceous feedstock into the reaction flow passage of a carbon blackreactor, such as the zone 6, through a first feedstock tube 52. Thefeedstock is preferably introduced along the longitudinal axis of thereactor. A second feedstock tube 53 is positioned parallel to the firstfeedstock tube 52. The second feedstock tube 53 is then shifted into theposition which was occupied by the first feedstock tube, which, in thepreferred embodiment, would be in axial alignment with the reaction flowpassage in the carbon black reactor. The carbonaceous feedstock is thenintroduced from the source 58 axially into the carbon black reactorthrough the second feedstock tube. Generally, the first feedstock tubeis shifted out of axial alignment with the reaction flow passage in thereactor prior to the shifting of the second feedstock tube into axialalignment with the reaction flow passage in the carbon black reactor.Prior to shifting the second feedstock tube into axial alignment withthe reaction flow passage in the carbon black reactor, it is desirableto terminate the flow of carbonaceous feedstock through the firstfeedstock tube, in order to avoid feedstock deposition on the hotrefractory defining the reaction flow passage. In the apparatus shown inthe figures, the second feedstock tube revolves into axial alignmentwith the reaction flow passage in the carbon black reactor and the firstfeedstock tube is revolves out of alignment with the reaction flowpassage of the carbon black reactor.

This can be accomplished by positioning the two feedstock tubes parallelto one another as shown in FIG. 1. Flow of carbonaceous feedstock to theoil tube 52 is discontinued by shutting valve 62. Collar 40 is loosened.A wrench is applied to the nut 44 and plate 18 is rotated until thesecond tubular member 53 is in axial alignment with the reaction flowpassage, usually 180°. Collar 40 is tightened. Valve 63 is open and theflow of carbonaceous feedstock into the reactor is resumed.

A Typical Reactor 2 can have dimensions set forth as follows:

    ______________________________________                                        Precombustion Zone 6:                                                         Diameter, inches,  39                                                         Length, inches     12                                                         Converging Zone:                                                              Inlet Diameter, inches                                                                           14                                                         Outlet Diameter, inches                                                                          8                                                          Diverging Zone:                                                               Inlet Diameter,inches,                                                                           8                                                          Outlet Diameter, inches                                                                          14                                                         Tangential Tunnels 76:                                                        Diameter, inches,  8                                                          Passage 28:                                                                   Diameter, inches,  10                                                         Tubes 54 and 55:                                                              Diameter, inches   3                                                          Tubes 52 and 53:                                                              Diameter, inches,  1                                                          (nozzle on top)                                                               Plate 18:                                                                     Diameter, inches,  11.5                                                       Thickness, inches, 0.25                                                       ______________________________________                                    

The metal parts can be formed from 316 or better stainless steel.

While there have been illustrated and described certain preferredembodiments of the invention, it is not to be construed as so limitedexcept to the extent of such limitations as found in the claims.

That which is claimed is:
 1. A method for producing carbon black whereinthe feedstock tubes are changed comprising(a) introducing a carbonaceousfeedstock into the reaction flow passage of a carbon black reactorthrough a first feedstock tube; (b) positioning a second feedstock tubeparallel to the first feedstock tube; (c) shifting the second feedstocktube into the position which was occupied by the first feedstock tube;(d) introducing the carbonaceous feedstock into the carbon black reactorthrough the second feedstock tube; and (e) terminating the flow ofcarbonaceous feedstock through the first feedstock tube.
 2. A method asin claim 1 wherein the carbonaceous feedstock is introduced axially intothe reaction flow passage of the carbon black reactor through the firstfeedstock tube, wherein, the second feedstock tube is shifted into axialalignment with the reaction flow passage, and wherein the carbonaceousfeedstock is introduced axially into the carbon black reactor throughthe second feedstock tube.
 3. A method as in claim 2 further comprisingshifting the first feedstock tube out of axial alignment with thereaction flow passage of the carbon black reactor prior to shifting thesecond feedstock tube into axial alignment with the reaction flowpassage in the carbon black reactor.
 4. A method as in claim 3 furthercomprising terminating the flow of carbonaceous feedstock through thefirst feedstock tube prior to shifting the second feedstock tube intoaxial alignment with the reaction flow passage in the carbon blackreactor.
 5. A method as in claim 4 wherein the second feedstock tuberevolves into axial alignment with the reaction flow passage in thecarbon black reactor and the first feedstock tube is revolved out ofalignment with the reaction flow passage of the carbon black reactor.